Field of the Invention
Embodiments of the present invention relate to the technical field of display, and more particular, to a method and a circuit for adjusting screen brightness and a display device having the circuit.
Description of the Related Art
With the development of mobile communication technique, mobile terminals, such as mobile phones, tablet PCs and the like, are coming in increasing numbers and play more and more important roles in our lives and works. In particular, the mobile terminals have some functions for users' entertainment, such as playing movies, a SMS function, a website browsing function, a QQ chatting function, displaying E-books, supporting video games, a photographic function and the like. These functions provide lots of fun for the users. When the users watch TV or chat on video by using the mobile terminals, the users may neglect gradual changes in light intensity of ambient environment. Such circumstances frequently happen when teenagers play video games. A brighter ambient environment may cause the problem that display contents on a display screen of the mobile terminal cannot be properly seen. In that case, the user usually moves the mobile terminal to be closer to his/her eyes so as to solve the above problem. On the contrary, a darker ambient environment will cause the display contents on the display screen of the mobile terminal to be too glaring for the user's eyes. Such problem is often neglected by the user. Mobile phones, as mobile terminals frequently used by a large number of users, are frequently moved between the brighter ambient environment and the darker ambient environment, for example, from day to night, from the indoors to the outdoors, from the inside of vehicles to the outside of vehicles, from the sunny environment to the darker environment and so on. That the movement between the brighter ambient environment and the darker ambient environment causes the problems of the display contents on the display screen not being properly seen and the screen being too glaring for the user's eyes severely harms the user's vision. Therefore, there is a need to provide a method and a system for adjusting a screen brightness, which can adjust a color brightness value and a contrast value of the display screen by detecting an intensity of an environment light, so that the effect of clearly displaying images and pictures can be achieved.
In the prior art, a CABC function (Content Adaptive Brightness Control) is generally used. With the CABC function, the color brightness value of the display screen is changed by adjusting backlight brightness. However, a timing controller (TCON) is first needed to support such function if the user wants to use it. At the same time, the user has to turn on such function if the user wants to use it. Then, the TCON processes (arithmetic processing) PWM (Pulse Width Modulation) signals, and thus the backlight brightness can be adjusted. In such case, there is needed a higher system cooperation requirement.